me neither. He got quite a number of things mixed up.
This article is rather old and I hope to be able to completely replace it soon. Here is a more recent one that does a better job in explaining what minerals in the water do to the beer:
http://braukaiser.com/wiki/index.php/How_to_read_a_water_report
Kai
So it’s in the filter? I thought it was just carbon in there. Good to know.
I didn’t know that BRITA is more than just a carbon filter. They also contain an ion exchange resin:
The content of the original BRITA cartridge is an experienced mixture of ion exchange resin and activated carbon, which is particularly suitable for this type of drinking water conditioning.
Kai
I just called my utility company to ask for a water report. They put connected me to their water chemistry expert (I forget the official title) and she emailed me a detailed, recent rport on the wate quality not only for the city, but for my particular sub-station as well, and it was free.
You’re lucky to get that kind of service. My water utility office is completely unhelpful. They don’t have a water chemistry expert on staff that I know of. It’s really a tiny operation, but fortunately the water is excellent.
Yes, ion exchange and carbon.
I always stayed away from using a Brita filter for brewing water because I knew it removed calcium. However, for brewers with high HCO3 alkalinity, it might be a very good choice. You can always add Calcium back and the water will probably taste better thanks to the activated Carbon.
I’m lucky to have a good friend as the lab scientist at my local water treatment facility. He runs my well water through the system tests for me at no charge, but I get the feeling he’s doing it on the sly. Occasionally he’ll test other club members’ well water for me, too, but I don’t want to overstep my friendship and get him fired.
My water utility is completely unhelpful, and the water is pretty crappy. 
I have to admit that I thought that the Brita filters were only activated carbon filters. Didn’t know that they also include a cation exchange resin.
I see that the cation exchange resin is charged with potassium instead of sodium which should reduce its impact to brewers.
I’m a little surprised by the reduction in total dissolved solids. If it were just the reaction from the cation exchange resin, the TDS would remain similar. But, it appears that the filter also decarbonates the water as it passes through. That causes the Ca and CO3 to precipitate onto the activated carbon surface. That is the reduction in temporary hardness that is touted by Brita.
I wouldn’t call the filter worthwhile, but it doesn’t really hurt the brewing water. Go for it.
Really? There’s an awful lot of people that want to reduce the HCO3 in their brewing water.
It should also remove much of the organic compounds that can make surface water taste foul in the warm weather.
I tried the Zerowater system, but even my softened water makes it unfeasible from a cost standpoint. I could use my RO and get pure water probably forever, though doing that somehow seems redundant.
There are far better alternatives for reducing HCO3 than a filter like that. Either acid addition or boiling are much better options.
In my statement above, I was speaking about the cation exchange filter. Activated Carbon is very useful to nearly anyone. Sorry for the confusion!
Alternatives, surely, but “far better” seems to be a matter of personal preference. A lot of homebrewers might find passing water over a filter readily available at the supermarket to be preferable to boiling or sourcing, storing and measuring acid.
The Brita’s reduction of 120 ppm HCO3 to 16 ppm seems pretty effective.